function BinarySearchTree() {
    var Node = function (key) {
        this.key = key;
        this.left = null;
        this.right = null;
    }
    var root = null;
    
    // 向树中插入一个键
    this.insert = function (key) {
        var newNode = new Node(key)
        if(root === null){
            root = newNode;
        }else{
            insertNode(root,newNode)
        }
    }
    
    var insertNode = function (node,newNode) {
        
    }
}